Asymmetric Hetero-Diels-Alder Addition of 1-Methoxybuta-1,3-diene to (2R)-N-Pyruvoyl- and (2R)-N-(Phenylglyoxyloyl)bornane-10,2-sultam

Cycloadditions of 1-methoxybuta-1,3-diene to (2R)-N-pyruvoyl and (2R)-N-(phenylglyoxyloyl)bornane-10,2-sultam ((−)- 1b and (−)- 1c , resp.) under high-pressure conditions are presented. The absolute configurations of the cycloadducts 2b,c and of their resulting reduced alcohols 3b,c are based on their X-ray analyses. The stereochemical course of these reactions is discussed and compared to the inverse diastereoselectivity observed for the analogous cycloaddition to (2R)-N-glyoxyloylbornane-10,2-sultam ( 1a )